19 Dec. 2006 revd 20.12.2007

CmpE 583 Fall 2006 OWL Lite- Classes & Individuals. 1

OWL Lite: Ch. 14- Deriving Classes

Ch. 15- Individuals

Atilla ELÇİ

19 Dec. 2006 Rev. 30.12.2008

CmpE 583 Fall 2006 OWL Lite- Classes & Individuals. 2

OWL Lite: Deriving New Classes

• Simple named subclass (rdfs:subClassOf property):– Specialization of another class<owl:Class rdfID=“TabletComputer”>

<rdfs:subClassOf rdf:resource=“#PC” /><rdfs:subClassOf rdf:resource=“#NoteBookComputer”/>

</owl:Class>– rdfs:subClassOf is a transitive property.

• Class equivalency (owl:equivalentClass property):– Identifies two synonymous classes<owl:Class rdfID=“LapTopComputer”>

<owl:equivalentClass rdf:resource=“#NoteBookComputer”/></owl:Class>

30 Dec. 2008 CmpE 583 Fall 2006 OWL Lite- Classes & Individuals. 3

OWL Lite: Deriving New Classes(continued)

• Intersection (owl:intersectionOf property):– A class composed of members common to all extensions.<owl:Class rdfID=“StudentsTakingBoth583And546”>

<owl:intersectionOf rdf:parseType=“Collection” /><owl:Class rdf:about=“#ClassOf583”/><owl:Class rdf:about=“#ClassOf546”/>

</owl:intersectionOf></owl:Class>

19 Dec. 2006Rev 30.12.2008

CmpE 583 Fall 2006 OWL Lite- Classes & Individuals. 4

OWL Lite: Describing Individuals

• Indiviuals are:– instances (members) of user-defined ontological classes (Tbox).– instantiated with RDF statements and encoded using RDF/XML– instance identifier is declared using rdf:ID attribute– rdf:type or typedNode syntax is used to associate with a class– individual identifier is a URIref– referenced using rdf:about or rdf:resource– individuals are collected in an instance or artifact file (ie, Abox).

As an RDF/XML file, it has header, body, and footer just like an ontology file.

• Contrast class vs subclass, individual vs instance:– As in OO, mostly.– But, check Tracy §15.1

19 Dec. 2006Rev 30.12.2008

CmpE 583 Fall 2006 OWL Lite- Classes & Individuals. 5

OWL Lite: Individuals• Instantiating using RDF Descriptions:

<rdf:Description rdf:ID=“student123”><rdf:type rdf:resource=“#ClassOf583”/>

</rdf:Description>• Instantiating using class name:

<ClassOf583 rdf:ID=“student123”></ClassOf583>

• Describing individuals while instantiating:– Insert attribute statement into the inner text

• Describing existing individuals: <ClassOf583 rdf:about=“#student123”>

<foaf:name>Ali Veli</foaf:name></ClassOf583>

19 Dec. 2006Rev 30.12.2008

CmpE 583 Fall 2006 OWL Lite- Classes & Individuals. 6

Individuals: relating them• Equivalent individuals (owl:sameAs):

– Means that two URIs refer to the same individual; used while declaring or describing an instance:

<rdf:Description rdf:ID=“student123”><owl:sameAs rdf:resource=“#studentNo123” />

</rdf:Description>– Usually used to “join” different ontology files.

• Differentiating individuals (owl:differentFrom):– Identifies pairwise distinct instances:<rdf:Description rdf:ID=“student123”>

<owl:differentFrom rdf:resource=“&classNS;student123” /></rdf:Description>– Supports inferencing

30.12.2008 CmpE 583 Fall 2006 OWL Lite- Classes & Individuals. 7

Individuals: relating them (continued)

• Differentiating Groups of individuals (owl:AllDifferent class + owl:distinctMembers property):– Shortcut declaration instead of many owl:differentFrom statements.<owl:AllDifferent>

<owl:distinctMembers rdf:parseType=“Collection”><comp:Computer rdf:about=“#gateWayPro” /> <comp:Computer rdf:about=“#toshibaSatellitePro” /> <comp:Computer rdf:about=“#hpCompaqPro” />

</owl:distinctMembers></owl:AllDifferent>

19 Dec. 2006 revd 20.12.2007

CmpE 583 Fall 2006 OWL Lite- Classes & Individuals. 8

Individuals (continued)

• Ref. Fig. 15-2. Summary of constructs describing individuals

19 Dec. 2006 revd 20.12.2007

CmpE 583 Fall 2006 OWL Lite- Classes & Individuals. 9

OWL Lite: Summary

• Fig. 11-2. Imports & Namespace Dependency Relationships

• Fig. 11-10. Header Concepts• Fig. 12-2. OWL Lite Classes & Properties• Fig. 13-6. Local Restriction Types• Fig. 13-7. Property Characteristics Taxonomy • Fig. 15-2. Constructs for Describing Individuals• Fig. 16-1. OWL Concept Type Separation Taxonomy

– NB: starred items are disjoint in OWL Lite.

• Table 16-1. OWL Lite Constructs• Table 16-2. OWL Lite Restriction Summary